Transmission factors and exposure to infections at work and invasive pneumococcal disease

Working in close contacts with coworkers or the general public may be associated with transmission of invasive pneumococcal disease (IPD). We investigated whether crowded workplaces, sharing surfaces, and exposure to infections were factors associated with IPD.

We studied 3,968 cases of IPD, and selected six controls for each case from the Swedish population registry with each control being assigned the index date of their corresponding case. We linked job histories to job-exposure matrices to assess different transmission dimensions of pneumococci, as well as occupational exposure to fumes. We used adjusted conditional logistic analyses to estimate the odds ratios (ORs) for IPD with 95% confidence intervals (95% CI).

ORs for IPD for the different transmission dimensions were increased moderately but were statistically significant. Compared to home-working or working alone, the highest odds was for Working mostly outside, or partly inside (OR 1.19, 95% CI 1.04-1.38). Estimates were higher in men for all dimensions, compared to women. The odds for IPD for Working mostly outside, or partly inside were 1.33 (95% CI 1.13-1.56) and 0.79 (95% CI 0.55-1.14) for men and women, respectively. Higher odds were seen for all transmission dimensions among those exposed to fumes, although CIs included unity. Contact with ill or infected patients did not increase the odds for IPD.

IPD was associated with working in close contact with coworkers or the general public, and with outside work, especially for men. Contact with infected patients or persons was not associated with IPD.